Simplify the following expression: $k = \dfrac{7q}{4} - \dfrac{6q}{5}$
In order to subtract expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $4$ and $5$ $\lcm(4, 5) = 20$ $ k = \dfrac{5}{5} \cdot \dfrac{7q}{4} - \dfrac{4}{4} \cdot \dfrac{6q}{5} $ $k = \dfrac{35q}{20} - \dfrac{24q}{20}$ $k = \dfrac{35q -24q}{20}$ $k = \dfrac{11q}{20}$